Exposure of strain A mice for 6 months to vinyl chloride, ethylene dibromide or ethylene oxide, cause concentration-related increases in numbers of pulmonary adenomas that were formed. This inexpensive model may be useful in helping to identify inhalant carcinogens. Mice were exposed to nitrogen dioxide following profiles with equal integrals of concentration with time but different maximum concentrations. The wet/dry lung weights were taken as a measure of pulmonary edema. The same study has been conducted with Acrolein as the exposure compound.